Art of hardening treads of cast-steel car-wheels.



'No. 728,271. IBATENTED MAY 19, 1903.

T. MITCHELL. I ART OF HARDENING TREADS 0F CAST STEEL GAR WHEELS.

APPLICATION FILED JUNE 20. 1902.

No. 728,2'7L

UNITED STATES Patented May 19, 1903.

PATENT QFFIcE.

THOMAS MITCHELL, OF CHESTER, PENNSYLVANIA, ASSIGN OR TO DANIEL EAGAN, OF PHILADELPHIA, PENNSYLVANIA.

ART OF HARDEN ING TREADS 0F CAST-:ST EEL CAR-WHEELS.

SPECIFICATION formingpart of Letters Yatent No. 728,271, dated y 1903- 7 Application filed June 20, 1902. Serial No. 112,424. (No specimens.)

To all whom, it Huey concern:

Be it known that I, THOMAS MITCHELL, a citizen of the United States, residing in the city of Chester, in the county of Delaware and State of Pennsylvania, have invented certain new and useful Improvements in the Art of Hardening the Treads of Cast- Steel Car- Wheels, of which the following is a specification.

My invention relates to the hardening of the rims of cast steel car wheels, and its object is the provision of an economical, simple, and easily conducted, operation for accomplishing such result.

The general basis of my improvement consists in the application, through a suitable mechanical agency, of air under pressure to the rim or tread of a hot steel car wheel, while movement, preferably rotative, is contemporaneously imparted to one of said devices with respect to the other, so that the relation between the agency and the wheel is varied proportionately to said movement.

In the rotation of the wheel, 'for example, (in the particular form of apparatus herein described as employed, in which the wheel rotates), the diderent portions of its tread and the locality or point of discharge of the air constantly vary with relation to each other.

The locality of discharge of the air may, in the described apparatus, be considered as the inner circumferential mouth or opening of the boxing or casing.

Manifestly, the circumferential portions of the wheel are in the successive positions occupied by the wheel, in the rotation which the described apparatus imparts to such wheel, progressively brought opposite to all the successive circumferential portions of said mouth or opening, so that a given point of the wheel tread varies, proportionatelyto the relative movement as between the wheel and the easing, its relation to any given point of the inner opening or mouth of the boxing or casin g. Hence, although ,in the form of apparatus depicted the relation of the axis of the wheel to the axis of the casing is not varied in the operation of the parts, the relation between the tread of the wheel and the locality of the discharge of the air does vary as just described.

I I speak of the opening or mouth of the boxthe wheel tread.

The employment of air as a hardening fluidfor the treads of cast steel car wheels is not only advantageous in the ease with which it may be supplied and controlled, and the simplicity of the apparatus involved, but particularly advantageous by reason of the very effective results which may be accomplished, it being, byits use, in the manner hereinafterset forth, possible to produce. any desired hardening in the treads of wheels operated upon, and in treating a large number of such Wheels, to bring the rims of all to a uniform hardness.

In the accompanying drawings I illustrate an apparatus which may be conveniently emtice. The apparatus may, of course, be constructed otherwise than as shown in said drawings. r

In the drawings, Figure 1 is a view in side elevation,-partly in section,of an apparatus by the aid of which my invention may be practiced. I

Figure 2 is a top plan view of thesame. The construction of the apparatus shown in the accompanying drawings is as follows:

a is a rotatable carrier, consisting of asupporting plate, of diameter approximately the same as that of a wheel to be operated uponand an axial depending stem, which extends and the distributor m to the boxing or casing acts through said opening or mouth against 2 ployed in carrying my invention into practhrough a pair of sleeves b, carried on any suitable supports 0, and with respect to which sleeves said stem, with its supporting plate, is free for revolution.

Such revolution may be conveniently imparted to the carrier by providing the lower end of the stem with a driven bevel gear (1, engaging with a driving bevel gear e, supposed connected with any convenient source of power.

The supporting plate or head of the rotatable carrier is of circular plan, and is arranged in an opening in which it snugly fits, free for revolution, in a floor or platform f,

llllll ll ll lll l llll l W the upper face of the supporting plate being conveniently flush with that of the floor or platform.

A depending annular lip g is arranged at the edge of the opening in the platform f. h is an annular wall, conveniently located in a position in which it is concentric with respect to the carrier, upon said floor f, said wall having an inwardly extending lip 'i arranged above the floor a distance approxi-' mating the thickness of a car wheel.

, As will be observed, the portion of the floor f in the vicinity of the carrier, the wall h, and the lip 2', together constitute an annular three sided or hood-like boxing, having an inwardly facing endless opening, of breadth approximately equal to the thickness of a.

may be strengthened by the annular braces j as shown in Figure 1.

.k-is'a supply pipe assumed to be in communication with a source of supply of air under pressure, which pipe extendsthrough a suitable opening to the interior of the annular hood-like boxing, where it is in communication with an annular tubular distributor m, the inner face of which is provided with a large number of small escape openings.

As will be understood from a contemplation of the drawings, the air, entering the distributer through the supply pipe,will' emerge through said escape openings in a great number of small jets directedtoward the rim or tread of the wheel n.

In the operation of the apparatus,the wheel, preferably but notrestrictively at about a cherry red heat, is placed on the carrier and the latter caused to rotate. is turned on through the supply pipe 70, and thereupon entering the distributor escapes from it in jets, playing against the rotating wheel. The arrangement is preferably such that the air escapes from the distributer more rapidly than it escapes through the crevices o andp, and consequently it accumulates in the hood,forming an air expansive cushion therein, which, as stated, presents against'the rim or tread of the wheel.

Although said mass or cushion of air in the hood may, when it has become sufiiciently dense, somewhat interfere with the direct action of the jets, as such, against the rim of the wheel, said jets will, notwithstanding, have a tendency constantly to aid in forcing the mass of air in the boxing against the rim of the wheel,--and, apart from the foregoing function, the distribution of the jet openings 65 of the distributor throughout its inner cirlllll ii iii W W l The air pressure cumferential face, occasions such a uniform distribution within the boxing of the air entering throughthe pipe 70 as tends to maintain an even pressure of the air against all parts-of the wheel rim.

As will be obvious, in the rotation of the wheel, during the time the air is being charged into the boxing, all parts of the wheel tread successively confront,rapidly and repeatedly, all the regions of the opening of the boxing, consequently, between the movement of the wheel and that of the air, a very intimate contact is established betweensaid tread and air, and as a result, great uniformity of the action of hardening is insured.

For ordinary purposes air at atmospheric temperatures may be charged to the distributer, but, if desired, air at a lower temperature may be charged thereto for the purpose of accelerating or increasing the effectiveness of the operation.

The apparatus herein described forms the subject of a separate application for Letters Patent duly executed by me and filed contemporaneously herewith as Serial No. 112,425.

It is, of course, to be understood that the air employed need not be perfectly dry, but may be more or less saturated with any suitable liquid such as water or oil, or with such air may be commingled any ingredient which may be found useful for the purpose.

I find that the hardening action due to the carrying of the air against the" tread of the wheel is most perfectly accomplished when the operation herein described, beginning as stated, preferably when the wheel is at about a cherry red heat,is continued until the wheel is cold.

Manifestly when it is required to produce wheels not. of the greatest hardness as to their rims, the operator in charge of the machine will turn ed the air before the casting becomes cold.

In other words, by regulating the length of exposure of the wheel to the air, the'hardness of the tread may be correspondingly and accurately regulated.

Having thus described my invention, I

claim- 1. The improvement in the art of hardening the treads of cast steel car wheels which consists in'rot'ativcly moving a wheel and in theapplication to the tread of such wheel,

while such wheel is hot, and during its movement, of air under-pressure.

2. The improvement in the art of hardening the treads of cast steel car wheels, which consists in rotating said wheels while hot and, during such rotation, discharging jets of air, under pressure, against such treads, the jets being confined within an inclosure across an opening in which the wheel tread presents.

3. The improvement in the art of hardening the tread of a cast steel car wheel, which consists in maintaining the tread of said ll ll" W ll ll ll wheel, while hot, in contact with a cushion of confined air under pressure and occasioning the rotation of said wheel.

4. The improvement in the art of hardening the tread of a cast steel car wheel, which consists in rotating said wheel, while hot, maintaining the tread of said wheel during such rotation at the mouth of an annular inclosure, and discharging under pressure within said inclos'nre a seriesof jets of air.

5. The improvement in the art of hardening the tread of a cast steel car wheel, which consists in rotating said'wheel with its tread in contact with a mass or cushion of air under pressure, and contained within an annular hood or boxing, said mass or cushion of air being supplied by discharging'air within said hood or boxing, in jets, at a multiplicity of points, said jets being directed against the tread of the wheel.

6. The improvement in the'art of hardening the rims of caststeel car wheels, which consists in moving said wheels and in subjecting them at an elevated temperature, and while moving, to the action of air under pressure, the subjection of said wheel to said air being continued until the wheel is cold.

7. The process of hardening the tread of a metal car wheel, which consists in subjecting the tread of such a wheel, while said wheel is hot, tothe action of air, partially confined and under pressure, and contemporaneously varying the relation which said wheel tread bears to the partially confined air. v

8. The process of hardening the treads of metal car wheels, which consists in subjecting the tread of such a wheel, while said wheel is at an elevated temperature, to the action of compressed air, the subjection of said wheel tread to said air being continued until the wheel is cold, and in varying the relation between a selected point of said wheel tread and the locality of the discharge of the air, during said operation.

9. The process of hardening the rims of metal car wheels, which consists in subjecting the tread of a wheel, while said wheel is at an elevated temperature, to the action of air under pressure, the subjection of said wheel tossaid air being continued until the wheel is cold, and during said operation, in

progressively varying the relation between said wheel tread and the locality of discharge of the air. a

In testimony that I claim the foregoing as my invention 1 have hereunto signed myname this 12th day of June, A. D. 1902. f THOMAS MITCHELL.

- In presence of- Trros."K. LANCASTER, 8-. SALOME Bnooxn. 

